Droid Razr loses signal; goes between 3G and 4G; Freezes frequently; I'll select an email to open and it will jump to another and open it. This happens not just in email also texts. It has been acting very erratically this year. I took it in last week and they replaced a scratched SIM card. Now I'm still losing signal. What is up? Anyone else having trouble? This is the second phone this year. The first one got really hot and Verizon finally replaced it.